Platforms · Software · Providers · Markets
The UK Financial Conduct Authority has finalised changes to transaction reporting under MiFIR, cutting the number of reportable fields from 65 to 52. The revised rules are due to take full effect on 3 April 2028, and the regulator says the changes could lower costs for the industry by more than £100 million annually.
The FCA also estimates that firms currently spend £493 million each year on transaction reporting. The reform removes around seven million instruments traded only on EU venues from UK reporting and ends duplicate MiFIR reporting for FX derivatives. For technology and operations teams, the work will centre on identifying which data flows, validation rules and reporting processes need to change.
What the FCA is changing
The reduction in fields means firms will need to compare their current reporting outputs with the revised data requirements, rather than assume existing mappings will remain suitable. The FCA has not specified in the source material which individual fields will be removed. Firms will need to establish which of their internal records populate the fields that remain, and where a change in a data definition requires an adjustment upstream.
The removal of instruments traded exclusively on EU venues changes the population of instruments included in UK submissions. Firms should check how their systems identify venue and instrument eligibility, and whether those attributes are available consistently across trading, reference-data and reporting systems. The source does not state how firms should handle instruments with incomplete or conflicting venue information.
For FX derivatives, the end of duplicate reporting under MiFIR should prompt a review of the reporting path and any controls that identify duplicate submissions. Firms will need to confirm how the revised UK process interacts with their existing reporting arrangements. The rule change does not, by itself, explain what a firm should do where the same transaction is captured in more than one internal system.
Historical error correction is also changing: the maximum period for correcting past reporting mistakes will move from five years to three. Operations teams should check how that window is reflected in exception queues, escalation procedures and audit records. The source does not set out any new retention requirement, so firms should distinguish the correction period from their separate record-keeping obligations.
Which reporting systems face changes
The changes concern firms that report transactions under the UK MiFIR framework. The FCA has not given a breakdown of affected firm types or reporting volumes in the material available here, so firms will need to establish their own scope. That assessment should include the entities submitting reports, the instruments they cover and the systems that supply the required data.
Implementation is not limited to changing an output file. The FCA says firms will need to alter reporting systems, data management and validation processes. A useful first exercise is to trace a transaction from its source record through enrichment and validation to submission, then identify where the field count, instrument eligibility or FX derivative handling changes that flow. Firms can adopt some provisions before the full regime begins, but the source does not identify which ones.
Quinn Perrott, Co-CEO of TRAction, has highlighted the operational work required to adapt. The rule changes were among the UK regulatory developments covered in a Finance Magnates weekly review. Firms planning delivery will need to decide who owns the mapping changes, how revised validations will be tested and how evidence of the new process will be retained.
The integration question
For infrastructure leads, the central issue is whether the reporting stack can distinguish the records affected by each reform without disrupting other submissions. That means checking the links between instrument reference data, venue information, FX derivative workflows and the transaction-reporting engine. The FCA's cost estimate describes an industry-wide opportunity, not the cost or saving for any particular firm.
Before implementation, firms should ask their vendors and internal teams which interfaces will change, whether historical corrections will be handled differently and how early adoption will be supported. The FCA's 3 April 2028 date gives firms a deadline, but the source does not provide a technical specification or a migration timetable. Those details will determine how much work sits in configuration, data remediation and testing.
